U.S. patent application number 16/373317 was filed with the patent office on 2019-10-10 for semiconductor light-emitting apparatus having light reflection adjusting member of gray resin and its manufacturing method.
The applicant listed for this patent is STANLEY ELECTRIC CO., LTD.. Invention is credited to Satoshi Ando, Mitsunori Harada, Kaori Tachibana.
Application Number | 20190312187 16/373317 |
Document ID | / |
Family ID | 68097419 |
Filed Date | 2019-10-10 |
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United States Patent
Application |
20190312187 |
Kind Code |
A1 |
Harada; Mitsunori ; et
al. |
October 10, 2019 |
SEMICONDUCTOR LIGHT-EMITTING APPARATUS HAVING LIGHT REFLECTION
ADJUSTING MEMBER OF GRAY RESIN AND ITS MANUFACTURING METHOD
Abstract
A semiconductor light-emitting apparatus is constructed by a
wiring substrate, at least one semiconductor light-emitting element
provided on the wiring substrate, at least one
wavelength-converting member provided on the semiconductor
light-emitting element, and a light reflection adjusting member
directly covering a sidewall of the semiconductor light-emitting
element and a sidewall of the wavelength-converting member. The
light reflection adjusting member is formed of gray resin including
light reflecting fillers and light absorbing fillers for visible
light.
Inventors: |
Harada; Mitsunori; (Tokyo,
JP) ; Tachibana; Kaori; (Tokyo, JP) ; Ando;
Satoshi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STANLEY ELECTRIC CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
68097419 |
Appl. No.: |
16/373317 |
Filed: |
April 2, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 25/0753 20130101;
H01L 33/46 20130101; H01L 33/44 20130101; H01L 2933/0041 20130101;
H01L 33/60 20130101; H01L 2933/0058 20130101; H01L 33/505 20130101;
H01L 33/56 20130101; H01L 33/502 20130101; H01L 33/507
20130101 |
International
Class: |
H01L 33/60 20060101
H01L033/60; H01L 25/075 20060101 H01L025/075 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2018 |
JP |
2018-072290 |
Claims
1. A semiconductor light-emitting apparatus comprising: a wiring
substrate; at least one semiconductor light-emitting element
provided on said wiring substrate; at least one
wavelength-converting member provided on said semiconductor
light-emitting element; and a light reflection adjusting member
directly covering a sidewall of said semiconductor light-emitting
element and a sidewall of said wavelength-converting member, said
light reflection adjusting member comprising gray resin including
light reflecting fillers and light absorbing fillers for visible
light.
2. The semiconductor light-emitting apparatus as set forth in claim
1, wherein said gray resin is a mixture of white resin including
said light reflecting fillers and black resin including said light
absorbing fillers.
3. The semiconductor light-emitting apparatus as set forth in claim
1, wherein said light reflecting fillers comprise titanium oxide,
and said light absorbing fillers comprise carbon black.
4. The semiconductor light-emitting apparatus as set forth in claim
3, wherein a carbon concentration of said gray resin is 10 to 100
ppm.
5. The semiconductor light-emitting apparatus as set forth in claim
1, wherein said gray resin mainly includes silicone resin.
6. The semiconductor light-emitting apparatus as set forth in claim
2, wherein said white resin mainly includes silicone resin, and
said black resin mainly includes silicone resin.
7. The semiconductor light-emitting apparatus as set forth in claim
1, wherein a size of said wavelength-converting member is the same
as a size of a light-emitting area of said semiconductor
light-emitting element viewed from the top.
8. The semiconductor light-emitting apparatus as set forth in claim
1, wherein a size of said wavelength-converting member is smaller
than a size of a light-emitting area of said semiconductor
light-emitting element viewed from the top, said
wavelength-converting member being adhered by a transparent
adhesive layer to said semiconductor light-emitting element, said
transparent adhesive layer covering a lower part of the sidewall of
said wavelength-converting member.
9. The semiconductor light-emitting apparatus as set forth in claim
1, wherein a lower side of said wavelength-converting member is the
same as a size of a light-emitting area of said semiconductor
light-emitting element viewed from the top, an upper side of said
wavelength-converting member being smaller than the size of a
light-emitting area of said semiconductor light-emitting element
viewed from the top, the sidewall of said wavelength-converting
member comprising a lower vertical section in proximity to said
lower side, an upper vertical section in proximity to said upper
side, and a sloped section between said lower vertical section and
said upper vertical section.
10. The semiconductor light-emitting apparatus as set forth in
claim 1, further comprising a light transparent substrate provided
on said wavelength-converting member, said light reflection
adjusting member covering a sidewall of said light transparent
substrate.
11. The semiconductor light-emitting apparatus as set forth in
claim 10, wherein said wavelength-converting member comprises an
inorganic phosphor layer.
12. The semiconductor light-emitting apparatus as set forth in
claim 10, wherein said wavelength-converting member is adhered by a
transparent adhesive layer to said light transparent substrate.
13. The semiconductor light-emitting apparatus as set forth in
claim 1, wherein said at least one semiconductor light-emitting
element comprises multiple semiconductor light-emitting elements,
and said at least one wavelength-converting member comprises a
single wavelength-converting member.
14. The semiconductor light-emitting apparatus as set forth in
claim 1, wherein said at least one semiconductor light-emitting
element comprises multiple semiconductor light-emitting elements,
and said at least one wavelength-converting member comprises
multiple wavelength-converting members each provided on one of said
multiple semiconductor light-emitting elements, said semiconductor
light-emitting apparatus further comprising a light transparent
substrate provided on said multiple wavelength-converting
elements.
15. The semiconductor light-emitting apparatus as set forth in
claim 1, further comprising a frame provided on said wiring
substrate and adapted to surround said light reflection adjusting
member.
16. A method for manufacturing a semiconductor light-emitting
apparatus as set forth in claim 1, comprising: preparing white
resin including light reflecting fillers; preparing black resin
including light absorbing fillers; preparing a light reflection
adjusting member of gray resin by mixing said white resin with said
black resin; mounting a semiconductor light-emitting element on a
wiring substrate; adhering a wavelength-converting member by a
transparent adhesive layer to said semiconductor light-emitting
element; and directly covering a sidewall of said semiconductor
light-emitting element and a sidewall of said wavelength-converting
member.
17. The method as set forth in claim 16, further comprising
adhering a light transparent substrate on said
wavelength-converting member before said covering, said covering
further covering a sidewall of said light transparent
substrate.
18. The method as set forth in claim 16, further comprising
providing a frame on said wiring substrate before said covering,
said frame surrounding said semiconductor light-emitting element
and said wavelength-converting member.
Description
[0001] This application claims the priority benefit under 35 U.S.C.
.sctn. 119 to Japanese Patent Application No. JP2018-072290 filed
on Apr. 4, 2018, which disclosure is hereby incorporated in its
entirety by reference.
BACKGROUND
Field
[0002] The presently disclosed subject matter relates to a
semiconductor light-emitting apparatus such as a white-light
light-emitting diode (LED) apparatus and its manufacturing
method.
Description of the Related Art
[0003] Generally, a semiconductor light-emitting apparatus such as
a white-light LED apparatus is used as an illumination apparatus
such as a vehicle headlamp, a street lamp or a conventional
lamp.
[0004] A first prior art white-light LED apparatus is constructed
by a wiring substrate, a blue-light LED element provided on the
substrate, a wavelength-converting member made of phosphor provided
on the upper surface of the blue-light LED element for converting a
part of the blue light emitted by the blue-light LED element into
wavelength-converted light such as yellow light with a longer
wavelength than that of the emitted blue light of the blue-light
LED element, thereby mixing light directly emitted from the
blue-light LED element with the yellow light into desired light
such as white light, and a coverage member formed of a light
reflecting member made of white resin covering the sidewalls of the
blue-light LED element and the wavelength-converting member for
confining the light emitted from the blue-light LED element into
the wavelength-converting member, thus realizing a color evenness
characteristic (see: JP2010-219324A).
[0005] In the above-described first prior art white-light LED
apparatus, however, the light strayed in the light reflecting
member is not completely absorbed therein, so that a leakage of
light (glare) from a non-light-emitting area surrounding a
light-emitting area viewed from the top during an operation mode of
the first prior art white-light LED apparatus would be
increased.
[0006] In a second prior art white-light LED apparatus, a light
absorbing member made of black resin surrounding the light
reflecting member is added to the first prior art white-light LED
apparatus (see: JP2014-082525A). In this case, the light reflecting
member is skirt-shaped or fillet-shaped. That is, the coverage
member is formed of the light reflecting member (white resin) and
the light absorbing member (black resin).
[0007] In the above-described second prior art white-light LED
apparatus, the light strayed in the light reflecting member (white
resin) is absorbed by the light absorbing member (black resin),
which would decrease the leakage of light (glare) from the
non-light-emitting area viewed from the top during an operation
mode of the second prior art white-light LED apparatus.
[0008] In the above-described second prior art white-light LED
apparatus, however, the thickness of the light reflecting member
adjacent to the wavelength-converting member is small due to the
presence of the light absorbing member, so that the reflectivity of
the light reflecting member is decreased. As a result, the luminous
intensity of the light-emitting area viewed from the top during the
operation mode of the second prior art white-light LED apparatus
would be decreased.
[0009] Also, in the above-described second prior art LED apparatus,
the light absorbing member is close to the wavelength-converting
member, so that light from the sidewall of the
wavelength-converting member is absorbed by the light absorbing
member, which also would decrease the luminous intensity of the
light-emitting area viewed from the top during the operation mode
of the second prior art white-light LED apparatus.
SUMMARY
[0010] The presently disclosed subject matter seeks to solve the
above-described problems.
[0011] According to the presently disclosed subject matter, a
semiconductor light-emitting apparatus includes a wiring substrate,
at least one semiconductor light-emitting element provided on the
wiring substrate, at least one wavelength-converting member
provided on the semiconductor light-emitting element, and a light
reflection adjusting member directly covering a sidewall of the
semiconductor light-emitting element and a sidewall of the
wavelength-converting member. The light reflection adjusting member
is formed of gray resin including light reflecting fillers and
light absorbing fillers for visible light.
[0012] Also, a method for manufacturing the above-mentioned
semiconductor light-emitting apparatus includes preparing white
resin including light reflecting fillers, preparing black resin
including light absorbing fillers, preparing alight reflection
adjusting member of gray resin by mixing the white resin with the
black resin, mounting a semiconductor light-emitting element on a
wiring substrate, adhering a wavelength-converting member by a
transparent adhesive layer to the semiconductor light-emitting
element, and directly covering a sidewall of the semiconductor
light-emitting element and a sidewall of the wavelength-converting
member.
[0013] According to the presently disclosed subject matter, the
light leakage (glare) in a non-light-emitting area surrounding a
light-emitting area can be suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other advantages and features of the presently
disclosed subject matter will be more apparent from the following
description of certain embodiments, taken in conjunction with the
accompanying drawings, wherein:
[0015] FIG. 1A is a plan view illustrating a first embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter;
[0016] FIG. 1B is a cross-sectional view taken along the line B-B
in FIG. 1A;
[0017] FIG. 2A is an optical microscopic picture of texture of the
black resin prepared for the light reflection adjusting member of
FIGS. 1A and 1B;
[0018] FIG. 2B is an optical microscopic picture of texture of the
gray resin prepared for the light reflection adjusting member of
FIGS. 1A and 1B;
[0019] FIG. 3 is a diagram for showing the relative luminous
intensity distribution of the white-light LED apparatus of FIGS. 1A
and 1B;
[0020] FIG. 4A is a plan view illustrating a second embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter;
[0021] FIG. 4B is a cross-sectional view taken along the line B-B
in FIG. 4A;
[0022] FIG. 5A is a plan view illustrating a third embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter;
[0023] FIG. 5B is a cross-sectional view taken along the line B-B
in FIG. 5A;
[0024] FIGS. 6A, 6B, 6C and 6D are cross-sectional views for
explaining a method for cutting the wavelength-converting member of
FIGS. 5A and 5B;
[0025] FIG. 7A is a plan view illustrating a fourth embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter;
[0026] FIG. 7B is a cross-sectional view taken along the line B-B
in FIG. 7A;
[0027] FIG. 8A is a plan view illustrating a fifth embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter;
[0028] FIG. 8B is a cross-sectional view taken along the line B-B
in FIG. 8A;
[0029] FIG. 9A is a plan view illustrating a modification of the
white-light LED apparatus of FIGS. 1A and 1B;
[0030] FIG. 9B is a cross-sectional view taken along the line B-B
in FIG. 9A;
[0031] FIG. 10A is a plan view for explaining a method for
manufacturing the white-light LED apparatus of FIGS. 9A and 9B;
[0032] FIG. 10B is a partial enlargement of 10A surrounded by a
dotted line B in FIG. 10A;
[0033] FIG. 11 is a graph showing a carbon concentration relative
to glare characteristic of the light reflection adjusting member of
FIGS. 4A and 4B;
[0034] FIG. 12 is a graph showing a carbon concentration relative
to luminous flux reduction rate characteristic of the light
reflection adjusting member of FIGS. 4A and 4B;
[0035] FIG. 13A is a graph showing the reflectivity characteristic
of the cured surface of the light reflection adjusting member of
FIGS. 4A and 4B;
[0036] FIG. 13B is a graph showing the average reflectivity
characteristic of the cured surface of the light reflection
adjusting member of FIGS. 4A and 4B; and
[0037] FIG. 14 is a graph showing a carbon concentration relative
to average reflectivity characteristic of the light reflection
adjusting member of FIGS. 4A and 4B.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0038] FIG. 1A is a plan view illustrating a first embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter, and FIG. 1B is a cross-sectional view taken along
the line B-B in FIG. 1A.
[0039] In FIGS. 1A and 1B, the white-light LED apparatus is
constructed by a wiring substrate 1, two blue-light LED elements
2-1 and 2-2 mounted on the wiring substrate 1, a
wavelength-converting element (plate) 4 adhered via a transparent
adhesive layer 3 to the blue-light LED elements 2-1 and 2-2, a
frame 5 surrounding the peripheries of the blue-light LED elements
2-1 and 2-2 and the wavelength-converting member 4, and a coverage
member of a light reflection adjusting member 6 provided between
the blue-light LED elements 2-1 and 2-2 and the frame 5 and between
the wavelength-converting element 4 and the frame 5. That is, the
light reflection adjusting member 6 directly covers the sidewalls
of the blue-light LED elements 2-1 and 2-2 and the
wavelength-converting element 4. Also, the light reflection
adjusting member 6, which may, in this case, be replaced by a white
resin layer, is provided between the blue-light LED elements 2-1
and 2-2, to suppress the reduction of the luminous intensity
between the blue-light LED elements 2-1 and 2-2.
[0040] The substrate 1 is made of AlN ceramic, for example.
[0041] The blue-light LED elements 2-1 and 2-2 may be electrically
connected either in series with each other or in parallel with each
other.
[0042] The blue-light LED elements 2-1 and 2-2 are constructed by
an epitaxially-grown structure including a p-type semiconductor
layer, an active layer and an n-type semiconductor layer.
[0043] The transparent adhesive layer 3 is made of silicone resin,
epoxy resin, acryl resin polycarbonate resin or the like.
[0044] The wavelength-converting plate 4 is constructed by a
transparent resin plate made of silicone resin or epoxy resin into
which phosphor such as Y.sub.3Al.sub.5O.sub.12:Ce.sup.+3 (YAG) is
dispersed, a phosphor-coated glass plate or a phosphor sintered
alumina ceramic plate, to convert blue light into yellow light. The
size of the wavelength-converting member 4 is about the same as
that of the blue-light LED elements 2-1 and 2-2 including the gap
therebetween viewed from the top. Therefore, most of the light
emitted from the blue-light LED elements 2-1 and 2-2 is introduced
into the wavelength-converting member 4.
[0045] The light reflection adjusting member 6 is made of gray
resin where a small amount of light-absorbing black resin having a
light absorbing characteristic for visible light is added to a
large amount of light-reflecting white resin having a light
reflecting characteristic for visible light, exhibiting both light
reflecting and absorbing functions.
[0046] The light reflection adjusting member 6 is made of gray
resin including white resin where 25 wt % titanium oxide is mixed
as light reflecting fillers with silicone resin, for example, and
black resin where 1 wt % carbon black is mixed as light absorbing
fillers with silicone resin, for example. In this case, the white
resin and the black resin are mixed with a weight ratio of 99.5:0.5
to form the light reflection adjusting member 6, thus exhibiting a
gray light characteristic. The cured gray resin has a diffuse
reflectivity of 89%. Note that the light reflection adjusting
member 6 can be formed by adding a predetermined amount of titanium
oxide and a predetermined amount of carbon black to silicone resin,
simultaneously.
[0047] FIG. 2A is an optical microscopic picture of black resin
prepared in advance, and FIG. 2B is an optical microscopic picture
of gray resin obtained by using the black resin of FIG. 2A.
[0048] In FIG. 2A, which shows black resin where 1 wt % carbon
black is added to silicone resin, one primary chain-structured
aggregate composed of several 10 to 100 nm carbon particles has a
size of 50 to 1 .mu.m, and multiple primary chain-structured
aggregates are aggregated by a physical force such as a van der
Waals force into one secondary chain-structured aggregate with a
size of several .mu.m to absorb 380 to 780 nm visible light.
[0049] As explained above, the light reflection adjusting member 6
exhibits a light reflecting function by titanium oxide for visible
light, and also, a light absorbing function by carbon black for
visible light. As a result, the light absorbing function can be
exhibited without deteriorating the light reflecting function.
Thus, as illustrated in FIG. 3, during an operation mode of the
blue-light LED elements 2-1 and 2-2, the relative luminous
intensity RLI is hardly reduced in a light-emitting area A1 defined
by the wavelength-converting element 4, while the relative luminous
intensity RLI is reduced in a non-light-emitting area A2. As a
result, the glare in the non-light-emitting area A2 surrounding the
light-emitting area A1 can be suppressed. In FIG. 3, the size of
the light reflection adjusting member 6 is exaggerated.
[0050] A method for manufacturing the white-light LED apparatus of
FIGS. 1A and 1B is as follows. Note that gray resin is prepared in
advance by mixing white resin of silicone resin including 25 wt %
titanium oxide with black resin of silicone resin including 1 wt %
carbon black. First, blue-light LED elements 2-1 and 2-2 are
mounted on a wiring substrate 1. Next, a wavelength-converting
member (plate) 4 is adhered by a transparent adhesive layer 3 on
the blue-light LED elements 2-1 and 2-2. Next, a frame 5 is adhered
by adhesives (not shown) on the periphery of the wiring substrate
1. Finally, gray resin is coated and buried between the blue-light
LED elements 2-1 and 2-2 and the frame 5, between the blue-light
LED elements 2-1 and 2-2, and between the wavelength-converting
member (plate) 4 and the frame 5. Thus, the white-light LED
apparatus of FIGS. 1A and 1B is completed.
[0051] In FIGS. 1A and 1B, note that the number of blue-light LED
elements can be 1, 3 or more.
[0052] FIG. 4A is a plan view illustrating a second embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter, and FIG. 4B is a cross-sectional view taken along
the line B-B in FIG. 4A.
[0053] In FIGS. 4A and 4B, the blue-light LED elements 2-1 and 2-2
of FIGS. 1A and 1B are replaced by one blue-light LED element 2,
and the size of the wavelength-converting member (plate) 4 is
smaller than that of the blue-light LED element 2 viewed from the
top. In this case, the transparent adhesive layer 3 is skirt-shaped
or fillet-shaped to cover a part of the upper surface of the
blue-light LED element 2 and a part of the sidewall of the
wavelength-converting element 4. Since the size of the
wavelength-converting element 4 is smaller than that of the
blue-light LED element 2 viewed from the top, the light emitted
from the blue-light LED element 2 is effectively introduced via the
fillet-shaped transparent adhesive layer 3 into the
wavelength-converting element 4, thus realizing a high luminous
intensity light-emitting area A1. Even in FIGS. 4A and 4B, during
an operation mode of the blue-light LED element 2, the relative
luminous intensity RLI is hardly reduced in a light-emitting area
A1 defined by the wavelength-converting element 4, while the
relative luminous intensity RLI is reduced in a non-light-emitting
area A2. As a result, the glare in the non-light-emitting area A2
surrounding the light-emitting area A1 can be suppressed.
[0054] A method for manufacturing the white-light LED apparatus of
FIGS. 4A and 4B is as follows. Note that gray resin is prepared in
advance by mixing white resin of silicone resin including 25 wt %
titanium oxide with black resin of silicone resin including 1 wt %
carbon black. First, a blue-light LED element 2 is mounted on a
wiring substrate 1. Next, a wavelength-converting member (plate) 4
is adhered by a transparent adhesive layer 3 on the blue-light LED
element 2. In this case, the transparent adhesive layer 3 is coated
on a lower part of the sidewall of the wavelength-converting member
(plate) 4. Next, a frame 5 is adhered by adhesives (not shown) on
the periphery of the wiring substrate 1. Finally, gray resin is
coated and buried between the blue-light LED element 2 and the
frame 5 and between the wavelength-converting element 4 and the
frame 5. Thus, the white-light LED apparatus of FIGS. 4A and 4B is
completed.
[0055] In FIGS. 4A and 4B, note that the number of blue-light LED
elements can be 2 or more.
[0056] FIG. 5A is a plan view illustrating a third embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter, and FIG. 5B is a cross-sectional view taken along
the line B-B in FIG. 5A.
[0057] In FIGS. 5A and 5B, the wavelength-converting plate 4 is
skirt-shaped or fillet-shaped. That is, the size of the lower
surface of the wavelength-converting plate 4 is about the same as
the size of the light-emitting area A1 of the blue-light LED
elements 2-1 and 2-2 including the gap therebetween viewed from the
top. On the other hand, the size of the upper surface of the
wavelength-converting plate 4 is smaller than that of the
blue-light LED elements 2-1 and 2-2 viewed from the top. In more
detail, the sidewall of the wavelength-converting plate 4 is
constructed by a lower vertical section 4-1 in proximity to the
lower surface, an upper vertical section 4-2 in proximity to the
upper surface, and a sloped section 4-3 between the lower vertical
sections 4-1 and 4-2.
[0058] The lower vertical section 4-1, the upper vertical section
4-2 and the sloped section 4-3 of the wavelength-converting plate 4
are dependent upon the cutting method thereof as illustrated in
FIGS. 6A, 6B, 6C and 6D.
[0059] As illustrated in FIGS. 6A and 6B, a flat
wavelength-converting member 4' is cut at an interval "d" along a
first direction by a blade 601 whose width is "W". As a result, as
illustrated in FIG. 6C, wavelength-converting members 4, whose
upper length is precisely d-W, are sandwiched by sidewalls each
having an upper vertical section 4-2 and a sloped section 4-3.
Then, as illustrated in FIG. 6D, the lower portions of the
wavelength-converting members 4 are cut by another blade (not
shown) whose width is much smaller than "W", so that the
wavelength-converting members 4 have sidewalls each having a lower
vertical section 4-1. In this case, the lower length of each of the
wavelength-converting members 4 is precisely "d". Thus, the
wavelength-converting plate 4 has a lower size of "d" and an upper
size of "d-W" along the first direction. Similar cutting operations
using the blades are performed upon the wavelength-converting plate
4 along a second direction orthogonal to the first direction. Thus,
since the wavelength-converting member 4 is skirt-shaped or
fillet-shaped, the light emitted from the blue-light LED elements
2-1 and 2-2 are effectively introduced into the
wavelength-converting element 4, thus realizing a high luminous
intensity light-emitting area A1. Even in FIGS. 5A and 5B, during
an operation mode of the blue-light LED elements 2-1 and 2-2, the
relative luminous intensity RLI is hardly reduced in a
light-emitting area A1 defined by the wavelength-converting element
4, while the relative luminous intensity RLI is reduced in a
non-light-emitting area A2. As a result, the glare in the
non-light-emitting area A2 surrounding the light-emitting area A1
can be suppressed.
[0060] A method for manufacturing the white-light LED apparatus of
FIGS. 5A and 5B is as follows. Note that gray resin is prepared in
advance by mixing white resin of silicone resin including 25 wt %
titanium oxide with black resin of silicone resin including 1 wt %
carbon black. First, blue-light LED elements 2-1 and 2-2 are
mounted on a wiring substrate 1. Next, a fillet-shaped
wavelength-converting member (plate) 4 is adhered by a transparent
adhesive layer 3 on the blue-light LED elements 2-1 and 2-2. Next,
a frame 5 is adhered by adhesives (not shown) on the periphery of
the wiring substrate 1. Finally, gray resin is coated and buried
between the blue-light LED elements 2-1 and 2-2 and the frame 5,
between the blue-light LED elements 2-1 and 2-2, and between the
wavelength-converting element 4 and the frame 5. Thus, the
white-light LED apparatus of FIGS. 5A and 5B is completed.
[0061] In FIGS. 5A and 5B, note that the number of blue-light LED
elements can be 1, 3 or more.
[0062] FIG. 7A is a plan view illustrating a fourth embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter, and FIG. 7B is a cross-sectional view taken along
the line B-B in FIG. 7A.
[0063] In FIGS. 7A and 7B, the blue-light LED elements 2-1 and 2-2
of FIGS. 1A and 1B are replaced by one blue-light LED element 2, so
that the size of a wavelength-converting member 4'' is the same as
that of the blue-light LED element 2. Also, a light transparent
substrate 7 made of heat-resistant glass or the like is provided on
the wavelength-converting member 4''. In this case, the
wavelength-converting member 4'' is constructed by a 20 to 30 .mu.m
thick high-density inorganic phosphor layer which is obtained by
printing slurry of inorganic binders and phosphor such as YAG on a
surface of the light transparent substrate 7 and calcining the
slurry in advance. Therefore, the density of phosphor in the
wavelength-converting member 4'' can be increased. Also, the
thickness of the wavelength-converting member 4'' can be made
uniform by the light transparent substrate 7, so that color
unevenness can be suppressed. In this case, since the size of the
wavelength-converting element 4'' is the same as that of the
blue-light LED element 2 viewed from the top, the light emitted
from the blue-light LED element 2 is effectively introduced via the
transparent adhesive layer 3 into the wavelength-converting element
4'', thus realizing a high luminous intensity light-emitting area
A1. Even in FIGS. 7A and 7B, during an operation mode of the
blue-light LED element 2, the relative luminous intensity RLI is
hardly reduced in a light-emitting area A1 defined by the
wavelength-converting element 4'' and the light transparent
substrate 7, while the relative luminous intensity RLI is reduced
in a non-light-emitting area A2. As a result, the glare in the
non-light-emitting area A2 surrounding the light-emitting area A1
can be suppressed.
[0064] A method for manufacturing the white-light LED apparatus of
FIGS. 7A and 7B is as follows. Note that gray resin is prepared in
advance by mixing white resin of silicone resin including 25 wt %
titanium oxide with black resin of silicone resin including 1 wt %
carbon black. First, a blue-light LED element 2 is mounted on a
wiring substrate 1. Next, a light transparent substrate 7 on which
a wavelength-converting member (plate) 4'' is formed is adhered by
a transparent adhesive layer 3 on the blue-light LED element 2. In
this case, the transparent adhesive layer 3 is coated on a lower
part of the sidewall of the wavelength-converting member (plate) 4.
Next, a frame 5 is adhered by adhesives (not shown) on the
periphery of the wiring substrate 1. Finally, gray resin is coated
and buried between the blue-light LED element 2 and the frame 5 and
between the wavelength-converting element 4 and the frame 5. Thus,
the white-light LED apparatus of FIGS. 7A and 7B is completed.
[0065] In FIGS. 7A and 7B, note that the number of blue-light LED
elements can be 2 or more.
[0066] FIG. 8A is a plan view illustrating a fifth embodiment of
the white-light LED apparatus according to the presently disclosed
subject matter, and FIG. 8B is a cross-sectional view taken along
the line B-B in FIG. 8A. In FIGS. 8A and 8B, wavelength-converting
members (plates) 4-1 and 4-2 are adhered by transparent adhesive
layers 3-1 and 3-2 to the blue-light LED elements 2-1 and 2-2,
respectively, of FIGS. 1A and 1B. Also, the light reflection
adjusting member 6, which may, in this case, be replaced by a white
resin layer, is provided between the blue-light LED elements 2-1
and 2-2 and between the wavelength-converting members 4-1 and 4-2
to suppress the reduction of the luminous intensity between the
wavelength-converting members 4-1 and 4-2. Further, a light
transparent substrate 7 is adhered by a transparent adhesive layer
3' similar to the transparent adhesive layer 3 to the
wavelength-converting members (plates) 4-1 and 4-2. As a result,
even when the flatness of the blue-light LED element 2-1 is
different from that of the blue-light LED elements 2-2 and the
flatness of the wavelength-converting member 4-1 is different from
that of the wavelength-converting members 4-2, the flatness of a
light-emitting area A1 can be defined by the light transparent
substrate 7 so that the luminous intensity in the light-emitting
area A1 can be made uniform by the light transparent substrate 7.
Even in FIGS. 8A and 8B, during an operation mode of the blue-light
LED elements 2-1 and 2-2, the relative luminous intensity RLI is
hardly reduced in the light-emitting area A1 defined by the
wavelength-converting elements 4-1 and 4-2, while the relative
luminous intensity RLI is reduced in a non-light-emitting area A2.
As a result, the glare in the non-light-emitting area A2
surrounding the light-emitting area A1 can be suppressed.
[0067] A method for manufacturing the white-light LED apparatus of
FIGS. 8A and 8B is as follows. Note that gray resin is prepared in
advance by mixing white resin of silicone resin including 25 wt %
titanium oxide with black resin of silicone resin including 1 wt %
carbon black. First, blue-light LED elements 2-1 and 2-2 are
mounted on a wiring substrate 1. Next, wavelength-converting
members (plates) 4-1 and 4-2 are adhered by transparent adhesive
layers 3-1 and 3-2 on the blue-light LED elements 2-1 and 2-2,
respectively. Next, a light transparent substrate 7 is adhered by a
transparent adhesive layer 3' to the wavelength-converting members
(plates) 4-1 and 4-2. Next, a frame 5 is adhered by adhesives (not
shown) on the periphery of the wiring substrate 1. Finally, gray
resin is coated and buried between the blue-light LED elements 2-1
and 2-2 and the frame 5, and between the wavelength-converting
members 4-1 and 4-2 and the frame 5, and between the light
transparent substrate 7 and the frame 5. Thus, the white-light LED
apparatus of FIGS. 8A and 8B is completed.
[0068] In FIGS. 8A and 8B, note that the number of blue-light LED
elements can be 1, 3 or more.
[0069] FIG. 9A is a plan view illustrating a modification of the
white-light LED apparatus of FIGS. 1A and 1B, and FIG. 9B is a
cross-sectional view taken along the line B-B in FIG. 9A.
[0070] In FIGS. 9A and 9B, the frame 5 of FIGS. 1A and 1B is not
present.
[0071] A method for manufacturing the white-light LED apparatus of
FIGS. 9A and 9B is as follows. Note that gray resin is prepared in
advance by mixing white resin of silicone resin including 25 wt %
titanium oxide with black resin of silicone resin including 1 wt %
carbon black. First, referring to FIG. 10A, blue-light LED elements
2-1 and 2-2 are mounted on predetermined positions of a surface
wiring substrate 101. Next, wavelength-converting members (plates)
4 are adhered by a transparent adhesive layer 3 on the blue-light
LED elements 2-1 and 2-2. Next, an outer frame 105 is adhered by
adhesives (not shown) on the periphery of the surface wiring
substrate 101. Next, gray resin is coated and buried between the
blue-light LED elements 2-1 and 2-2 and the frame 105, between the
blue-light LED elements 2-1 and 2-2, and between the
wavelength-converting member (plate) 4 and the frame 105. Finally,
in a dicing process as illustrated in FIG. 10B, cutting operations
are carried out along the lines X and Y. Thus, multiple white-light
LED apparatuses of FIGS. 9A and 9B are completed. In this case, the
outer frame 105 is excluded from the completed white-light LED
apparatuses.
[0072] The modification of FIGS. 9A and 9B can be applied to the
white-light LED apparatus as illustrated in FIGS. 4A and 4B, FIGS.
5A and 5B, FIGS. 7A and 7B and FIGS. 8A and 8B.
[0073] FIG. 11 shows a carbon concentration relative to glare
characteristic of the light reflection adjusting member 6 of FIGS.
4A and 4B, the glare (%) is represented by
the glare (%)=(the luminous intensity of the non-light-emitting
area A2 at a distance of 0.2 mm from the edge of the light-emitting
area A1)/(the average luminous intensity of the light-emitting area
A1)
[0074] As illustrated in FIG. 11, when the carbon concentration is
less than 20 ppm, the glare is below 2%, and when the carbon
concentration is 100 ppm or more, the reduction of the glare is not
observed. Therefore, the optimum carbon concentration 0 CC is 10 to
100 ppm in view of the reduction effect of the glare.
[0075] FIG. 12 shows a carbon concentration relative to luminous
flux reduction rate characteristic of the light reflection
adjusting member 6 of FIGS. 4A and 4B, the glare (%) is represented
by
the luminous flux reduction rate (%)=1-(the luminous flux of the
light-emitting area A1)/(the luminous flux of the light-emitting
area A1 at the zero carbon concentration)
[0076] As illustrated in FIG. 12, as the carbon concentration
increases, the luminous flux reduction rate increases; in this
case, when the carbon concentration is more than 100 ppm, the
luminous flux reduction rate rapidly increases. Therefore, the
optimum carbon concentration 0 CC is also 10 to 100 ppm in view of
the reduction effect of the luminous flux.
[0077] As illustrated in FIG. 13A, which shows a reflectivity
relative to light wavelength characteristic of the cured surface of
the light reflection adjusting member 6 of FIGS. 4A and 4B, when
the carbon concentration C is increased from 0 ppm via 20 ppm, 50
ppm, 100 ppm and 250 ppm to 500 ppm, the reflectivity R of the
light reflection adjusting member 6 is decreased, and also, as the
wavelength of light is increased, the reflectivity R is decreased.
In FIG. 13B, which shows an average reflectivity relative to carbon
concentration characteristic of the light reflection adjusting
member 6 for 420 to 800 nm visible light, the average reflectivity
AR using gray resin where black resin with a carbon concentration
of 1% is added to silicone resin is substantially the same as the
average reflectivity AR using gray resin where black resin with a
carbon concentration of 2% is added to silicone resin.
[0078] In FIG. 14, which shows a carbon concentration relative to
average reflectivity characteristic of the light reflection
adjusting member 6 of FIGS. 4A and 4B, when the carbon
concentration is more than 100 ppm, the average reflectivity AR of
the light reflection adjusting member 6 rapidly decreases.
Therefore, the optimum carbon concentration 0 CC for reducing the
glare is 10 to 100 ppm. In this case, the average reflectivity AR
is
65%.ltoreq.AR.ltoreq.95%
preferably,
80%.ltoreq.AR.ltoreq.90%
[0079] As stated above, when gray resin is obtained by a mixture of
white resin including 25 wt % titanium oxide and black resin
including 1 wt % carbon black with a weight ratio of 99.5:0.5, the
carbon concentration C is
1%.times.0.5%=50 ppm
[0080] Thus, the optimum carbon concentration 0 CC from 10 to 100
ppm is satisfied, so that the average reflectivity AR of the
light-emitting area A1 would satisfy the relationship
65%.ltoreq.AR.ltoreq.95%. Generally, if based on a table of the
average reflectivity AR of the light-emitting area A1 as a function
of the concentration of titanium oxide in the white resin, the
concentration of carbon black in the black resin and the weight
ratio of the white resin to the black resin is prepared in advance,
an arbitrary average reflectivity AR from 65% to 95% can be easily
realized.
[0081] Note that, in the above-described embodiments, blue-light
LED elements are provided; however, other semiconductor
light-emitting elements such as other LED elements or laser diode
(LD) elements can be provided.
[0082] It will be apparent to those skilled in the art that various
modifications and variations can be made in the presently disclosed
subject matter without departing from the spirit or scope of the
presently disclosed subject matter. Thus, it is intended that the
presently disclosed subject matter covers the modifications and
variations of the presently disclosed subject matter provided they
come within the scope of the appended claims and their equivalents.
All related or prior art references described above and in the
Background section of the present specification are hereby
incorporated in their entirety by reference.
* * * * *